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Title: MHD equilibrium in toroidal systems with a helical magnetic axis

Thesis/Dissertation ·
OSTI ID:5344241

An asymptotic model based on the the stellarator expansion is developed to study MHD equilibria in toroidal systems with a helical magnetic axis. The ordering of the vacuum fields is based on the assumptions that the plasma radius is small with respect to the periodicity length of the helical axis, which is in turn small with respect to the toroidal circumference. The effects of plasma pressure are included. A characteristic coordinate system based on the lowest-order vacuum field lines is introduced. In this coordinate system, the equilibrium problem is reduced to a two-dimensional generalized partial differential equation of the Grad-Shafranov type. A stellarator expansion free-boundary equilibrium code is modified to solve the helical axis equations. The expansion model is used to predict the equilibrium properties of two representative stellarators, Asperator NP-3 and NP-4. Numerically determined flux surfaces, magnetic well, transform, and shear are presented. The equilibria show a toroidal Shafranov shift, and high-..beta.. values are achieved.

Research Organization:
Princeton Univ., NJ (USA)
OSTI ID:
5344241
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English